Globally, the olive oil processing industry is growing. It is a significant sector in the economy of the Mediterranean countries and with an increasing trend in other countries, such as USA. Along with the growth of this agro-industry sector, high rate of residues, namely olive pomace are produced. Olive pomace is an environmental problem due to its high phytotoxicity and cannot be discarded without any treatment (Valta K, Aggeli E, Papadaskalopoulou C, Panaretou V, Sotiropoulos A, Malamis D, et al. Adding Value to Olive Oil Production Through Waste and Wastewater Treatment and Valorisation: The Case of Greece. Waste and Biomass Valorization. 2015;6(5):913-25).
Olive pomace contains the remaining olive fat, water and a great amount of bioactive compounds (Roseelló-Soto E, Koubaa M, Moubarik A, Lopes R P, Saraiva J A, Boussetta N, et al. Emerging opportunities for the effective valorization of wastes and by-products generated during olive oil production process: Non-conventional methods for the recovery of high-added value compounds. Trends in Food Science & Technology. 2015;45(2):296-310).
Olive pomace production is strongly affected by seasonality (October to January). Usually, olive oil production units transfer and discharge olive pomace in large open-air containers to be stored through long periods till processing to olive pomace oil and extracted olive pomace.
Generally, olive pomace oil is obtained by extraction with chemical solvents, such as n-hexane. Afterwards, the final residue can be sold as raw material to burn.
Several works relate to olive pomace are available. For example, PT 105275 A that describes a process to produce blocks and granulates composed by olive pomace and cork dust. This process generates pellets with high heat energy. Another example, PT 105914 A describes the composition of an olive pomace extract mainly composed by hydroxytyrosol with impact in neurodegenerative disease.
Treated olive mill wastewater with different techniques has also been attempted, aiming to reduce olive mill wastewater phytotoxicity (Rusan M J, Albalasmeh A A, Zuraiqi S, and Bashabsheh M. Evaluation of Phytotoxicity Effect of Olive Mill Wastewater Treated by Different Technologies on Seed Germination of Barley (Hordeum Vulgare L.). Environmental Science Pollution Research. 2015;12:9127-35). Also, several studies are being conducted in composting wastes using olive pomace and other residues for soils fertilization (Chowdhury AKMB, Akratos C S, Vayenas D V, and Pavlou S. Olive Mill Waste Composting: A Review. International Biodeterioration & Biodegradation. 2013;85: 108-19).
Countries that usually have a tradition in olive oil production, such as Spain and Italy, have already some technologies focusing the recovery of bioactive compounds from olive pomace. Sabatini (2010) described different patents to obtain olive polyphenols concentrate using extraction and membrane separation techniques. The methodologies for preparation of hydroxytyrosol esters and tyrosol and/or hydroxytyrosol and procedures for the treatment of oil mill wastewaters allow a recovery of water up to 85% and highly pure tyrosol and hydroxytyrosol (Sabatini N. Recent Patents in Olive Oil Industry: New Technologies for the Recovery of Phenols Compounds from Olive Oil, Olive Oil Industrial by-Products and Waste Waters. Recent Patents on Food, Nutrition & Agriculture. 2010;2:154-9). None of those studies describe the destination of the final solid fraction.
These facts are disclosed in order to illustrate the technical problem addressed by the present disclosure.